The number of copies of a publication distributed by the publishing company. Circulation figures are available for all major publications. A newspaper’s circulation is the amount of copies it distributes on an average day. Circulation is one of the key elements used to determine advertising rates. Circulation may differ from the amount of copies sold, this may be referred to as  paid circulation, due to some newspapers distributing their print with no cost to the buyer.

See also:
Distribution
Advertising